Recall of a learned sequence of stimuli from a part of the sequence is important to predict future events and to act according to a plan. Some studies suggested that coherent theta (4-12Hz) and slow gamma (30-60Hz) oscillations in the hippocampal-prefrontal network in local field potential (LFP) and phase-locking of prefrontal cortex (PFC) spikes to hippocampal theta oscillation play critical roles in working memory (Jones & Wilson,2005; Sigurdsson et al.,2010), which could be a basic function for information process of sequence. In addition, some studies suggest directionality of functional connectivity that the hippocampus leads PFC (Adhikari et al.,2010; Jones & Wilson,2005; Siapas et al.,2005). However, it is not clear whether these phenomena are related to recall of sequence memory. Thus, we are recording spikes and LFPs from the hippocampus and PFC simultaneously while the rats are performing the cued serial reaction time task (Ishino & Sakurai, 2014), in which three successive nose-poke responses to successively presented different holes are required. In the task, only two sequences of holes are fixed and learned in advance (predictable sequences) and the other sequences of holes are not fixed (unpredictable sequences). We are analyzing coherence of LFP oscillations, spike-LFP phase locking and directionality of functional connectivity between the hippocampus and PFC, and will report preliminary neuronal data related to the recall of learned sequences.